The objectives of the proposed research are to examine the molecular and genetic bases for morphogenetic movements and cell differentiation in the fruiting myxobacterium Stigmatella aurantiaca. This is a procaryote that lives in a multicellular condition and undergoes changes in cell adhesiveness and directed cell movements that result in the construction of multicellular fruiting bodies housing differentiated myxospores. Morphogenetic movements and changes in cell adhesion are central to normal embryological development as well as to the growth and spread of cancer cells. The approach will be to identify the molecules responsible for cell adhesion and to identify extracellular signaling molecules used by the cells during morphogenetic movements. Light has been observed to have a pronounced effect on morphogenesis. The proposed research will investigate the morphogenetic effects of light in molecular terms.